With supplies nearly exhausted, a mass H1N1 vaccination clinic in Louisville ended ahead of schedule Thursday afternoon.Health department officials shut down the lines at 1pm, seven hours before the scheduled end of the clinic outside Papa John's Cardinal Stadium.More than 19,000 doses of the vaccine were administered during the clinic that began Wednesday morning.Health deparment director Dr. Adewale Troutman says he's not sure when federal officials will ship more doses to Louisville."It's very difficult to say. We expect shipments on a regular basis. Production delays are still pushing out vaccine on a weekly basis and we like other municipalities around the country expect to get it on a regular basis. It's very difficult to pin down how many and when," Troutman said.This week's clinic was intended for people at high risk of contracting H1N1 flu, but others seeking the vaccine were not turned away.